López Ramis, VíctorRe, Michela TatianaCanfrán Arrabe, SusanaArenillas Baquero, MarioGaspar Simón, Ignacio deÁlvarez Gómez De Segura, IgnacioBlanco Murcia, Francisco Javier2025-10-222025-10-222025López-Ramis, V., Re, M., Canfrán, S., Arenillas, M., De Gaspar, I., Gómez De Segura, I. A., & Blanco Murcia, J. (2025). Description of an ultrasound-guided technique for pudendal nerve block in sheep. Veterinary Anaesthesia and Analgesia, 52(2), 236-243. https://doi.org/10.1016/j.vaa.2024.11.0431467-298710.1016/j.vaa.2024.11.043https://hdl.handle.net/20.500.14352/125276Authors contributions VLR: study design, data acquisition, data interpretation, manuscript preparation. MR: study design, data acquisition, data interpretation, manuscript preparation, revision, and approval. JBM: study design, data acquisition, data interpre tation, manuscript preparation, revision and approval. SC: study design, data interpretation, manuscript preparation, revision and approval. MA: study design, data acquisition, data interpretation, manuscript preparation, revision and approval. IDG: anatomical evaluation and guided dissection. IAGS: study design, data interpretation, manuscript preparation, revision and approval. All authors read and approved the final version of the manuscript.Objective To describe an ultrasound-guided technique for anaesthesia of the pudendal nerve with evaluation of the anatomical spread of a bupivacaine-methylene blue solu tion in sheep. Study design Prospective, experimental study. Animals A total of seven adult experimental sheep and one sheep cadaver. Methods The study had two phases. First, the anatomy and ultrasound imaging of the gluteal region, caudal to the region of tuber coxae was reviewed in one sheep cadaver. Second, in seven healthy sedated sheep, a linear transducer (8e13 MHz) was positioned on the lateral area of the hip to identify pu dendal vessels at the level of the ischial spine ventral to the sacrotuberous ligament. The right and left pudendal nerves area were injected with 0.1 mL kg-1 of a 1:1 solution of bupivacaine-methylene blue. The ultrasound image quality was considered as excellent, good, or poor. Following eutha nasia, both pudendal areas were dissected and the staining of the nerves assessed, expressed as the percentage of success (%) and compared with the chi-square test. Results The relevant ultrasound landmarks were visualized in both areas of all sheep, with an excellent visualization of the landmarks before and during injection in most cases (13/14). On dissection, methylene blue dispersion was observed surrounding the pudendal nerve, with at least 1 cm length in 13/14 cases (93%; the remainder partially stained). No evidence of dye was found around the sciatic nerve in any case nor was there any evidence of haema toma or faecal contamination within the punctured area. Conclusions and clinical relevance Ultrasound-guided in jection with 0.1 mL kg-1 in close proximity to the pudendal nerve at the ischial spine level resulted in a high success rate o nerve staining. This procedure may be a suitable technique for pudendal nerve blockade providing analgesia for common reproductive or perineal surgical procedures in sheep.engjournal article1467-2995https://doi.org/10.1016/j.vaa.2024.11.043restricted access636.09Conduction anaesthesiaDomestic sheepLocal anaesthesiaPudendal nerveUltrasonographyVeterinaria3109 Ciencias Veterinarias